function Bomb(){
    var time;
    this.start=function(){
        time =setTimeout(()=>{
            console.log("bomb!");
        },3000);
    }
    this.clear=function(){
        clearTimeout(time);
    }
}
var b1 = new Bomb();
var b2 = new Bomb();

b1.start();
b2.start();
setTimeout(() => {
    b2.clear();
}, 1000);